Crystalline alumino silicate-silica-alumina gel hydrocarbon conversion catalysts and processes for producing same

ABSTRACT

This invention relates to catalysts containing crystalline alumino-silicate zeolite and hydrothermally treated silica-alumina cogels and the employment of the same as cracking catalysts.

BACKGROUND OF THE INVENTION

This application is a continuation-in-part of applications, Ser. No.935,628; filed Aug. 21, 1978; and Ser. No. 769,118; filed Feb. 16, 1977now U.S. Pat. No. 4,142,995 and Ser. No. 874,755; filed Feb. 3, 1974 nowU.S. Pat. No. 4,198,310 and of application Ser. No. 874,754, filed Feb.3, 1978, and application Ser. No. 3,793, filed Jan. 16, 1979.

In the aforesaid applications Ser. No. 935,628 and copending applicationSer. No. 3,879; filed Jan. 16, 1979, and Ser. No. 9,487; filed Feb. 5,1979, we have disclosed our invention whereby silica-alumina cogels maybe hydrothermally treated to produce active catalysts. In applicationSer. No. 874,754 and U.S. Pat. No. 4,058,484, we have disclosed ourinventions whereby sodium containing zeolites are exchanged underpressure to reduce the sodium content of the zeolite and to includeother cations into the zeolite.

In our copending applications, Ser. No. 874,755 and application Ser. No.769,118 we have disclosed our inventions for combining the silicaalumina cogel with the zeolite, either by mixing the cogel with thezeolite or encapsulating the zeolite with the silica-alumina cogel.

In our copending applications Ser. No. 935,628, Ser. No. 3,879, and Ser.No. 9,487, we have disclosed our invention relating to the improvementof the catalytic cracking activity of silica-alumina cogels which aresubstantially free of sodium is improved by digesting the cogel at anelevated temperature in the presence of solutions containing hydrogen,ammonium or polyvalent cations such as rare earth or alkaline earthcations. The above Applications are incorporated herein by thisreference. Reference may be made to the above Applications for adiscussion of the prior art.

STATEMENT OF THE INVENTION

This application relates to combinations of hydrothermally treatedsilica-alumina gels with crystalline alumina silicate zeolites (CAS),having low content of alkali metal and to methods of producing the same.Such CAS zeolites include the sieve zeolites, for example, faujasite,for example, the so-called molecular X and Y zeolites. (See Milton, U.S.Pat. No. 2,822,244 and Breck, U.S. Pat. No. 3,130,007), and mordanite.

The gel may, according to our invention, be separately treated in thepresence of a monovalent cation other than alkali metal cation forexample H, NH₄ alkaline earth or rare earth cations and combined withthe crystalline aluminosilicate (CAS) zeolite which has a suitable lowalkali metal content.

Instead, the CAS zeolite having a relatively high alkali metal contentis combined with the cogel and the mixture is hydrothermally treated tohydrothermally activate the cogel and reduce the alkali metal content ofthe CAS zeolite. (See our U.S. Pat. No. 4,085,069, and copendingapplication Ser. No. 869,856, filed Jan. 16, 1978, and Ser. No. 877,754,filed Feb. 3, 1978, and Ser. No. 808,268, filed June 20, 1977.

The combination of the CAS zeolite and the cogel according to ourinvention may be made by mixing the GAS zeolite having a relatively highalkali metal content with the gel forming ingredients to encapsulate theCAS zeolite and to hydrothermally treat the mixture to so activate thegel and reduce the sodium content of the CAS zeolite.

The gels which are treated according to our invention may be formed byany of the procedures employed in the prior art.

Gels which have ammonium cations associates with the gel are hereinreferred to as ammoniated gels. Such gels for example may containsubstantial concentrations of ammonium cations.

Gels may also be formed substantially free of ammonium cations byreacting sodium aluminate with an aluminum salt and maintaining themixture on the acid side. The sodium content of the acid gel may besimilar to that of the ammoniated gel. We refer to such gels as acidgels.

While the hydrothermal treatment of the acid gel according to theprocess of our invention produces a gel of substantial catalyticactivity superior activity is obtained by treatment of the ammoniatedgel.

In the case of the ammoniated gels the improvement in catalytic activityobtained by the hydrothermal treatment is increased by treatment at atemperature in excess of about 150° F. In such ammoniated gels,preferably those containing SiO₂ /Al₂ O₃ molar ratio of less than about3, substantially free of sodium cations, the catalytic activity of thegel is increased to a degree which is dependent on the concentration ofthe ammonium cation associated with the treated gel. Preferably the NH₄content of the gel, expressed as NH₃, is in the range from less thanabout 0.3 and preferably less than 0.2 equivalents of ammonium per moleof Al₂ O₃.

The activity produced from such gels depends on the conditions of thehydrothermal treatment and the ionic system. A crystalline phase maydevelop or the gel may remain amorphous and a reduction in the ammoniumcontent of the gel and an increase in the catalytic activity of the gelmay be obtained in both cases.

The process of our invention includes the treatment of a silica-aluminacogel containing less than about 1% of Na₂ O based on the cogel on avolatile free basis by a hydrolytic treatment of the gel. The hydrolysesmay be carried out in the presence of monovalent cations other thanalkali metal cations such as hydrogen or ammonium or polyvalent cationssuch as rare earth cations or alkaline metal cations. We prefer to carryout the hydrothermal treatment under acid conditions rather than athigher pH as for example under alkaline conditions. A superioramplification in the activity on reductions in ammonium content in thegel is obtained by treatment under acid conditions.

Under relatively mild and controlled hydrothermal conditions oftemperatures below about 300° F., the reaction of the gel having low Na₂O content, results in an amorphous gel which exhibits superior catalyticactivity as compared with the original gel. At temperatures above about300° F. and at suitable concentrations of cations and time of digestiona crystalline phase develops.

The crystalline phase generated under acid conditions by reactions withrare earth salts under temperature in excess of 300° F. have an activitywhich is characteristic of the so called ultra-stable crackingcatalysts.

The crystalline phase is characterized by an X-Ray spectrum in whichcharacteristic peaks occur.

Excessive exposure of the gel for prolonged periods of time particularlyat the higher temperatures may deliteriously affect the catalyticactivity of the deammoniated gel although a successful reduction inammonium content is achieved.

For purposes of describing the result of the process of treating theammoniated gel with water or a solution of a salt, whereby the NH₄content of the gel is reduced, we refer to the process as an "exchange"and the cation as "associated" with the gel.

The reduction in the ammonium content of the cogel by the process of ourinvention occurs in the presence of acid hydrogen or ammonium salts thatis in the absence of metallic cations. We observe, however, that in thecase of such hydrothermal treatment with polyvalent cations the treatedgel has associated therewith the polyvalent cations employed in thehydrothermal treatment. The polyvalent cations may be alkaline earthcations or the metallic cations of the transition element or thelanthanide series of the periodic table with rare earth cations of Group3b and the lanthanide period of the periodic table preferred. Such rareearth cations are available commercially as mixtures (see infra).

The hydrothermal treatment improves the activity of the silica-aluminagel whether the gel is ammoniated or is an acid gel.

When the acid cogel of substantially the same SiO₂ /Al₂ O₃ molar ratio,which is the same as in the case of ammoniated gel, that is one free ofammonium cations, is reacted with rare earth cations under hydrothermalconditions, we obtained an amorphous gel of substantial activity but ofan activity inferior to that produced by like treatment of an ammoniatedgel.

We prefer to hydrothermally treat the ammoniated silica-alumina cogel inthe presence of a water solution of rare earth salts under acidconditions preferably at a pH from about 4 to about 6 and attemperatures in the range of about 150° F. to about 450° F. undersuitable autogenous pressure conditions for a period of about two tofour hours. Excessive temperatures or excessive acidity or excessiveduration of treatment will depreciate the resultant activity, from thatwhich is obtained under the more controlled reaction conditions.

The gel is mixed with water or water containing a suitable salt,acidified, if necessary to the desired pH, and then heated attemperatures from about 150° F. to about 450° F. under autogenouspressure where the temperature is above the boiling point. In such casesa temperature is selected to be in the range between about 250° F. and450° F.

The crystalline-alumino silicate zeolite which may be combined with thecogel according to our invention includes the so called molecular sievezeolites. (See Breck, "Zeolite Molecular Sieve" published by John Wiley& Company, 1974), preferably the zeolite which we wish to employ are ofthe faujasite type, that is the so called X zeolites (see Milton, U.S.Pat. No. 2,882,244) or the so called Y zeolite (see Breck, U.S. Pat. No.3,130,007).

The gel and zeolite may, but need not, be combined with a matrixmaterial, such as kaolin clays, for example ball clay or halloysite, oracid treated halloysite or an inorganic oxide gel, for example silicagel or the hydrated alumina such as pseudoboehmite and mixtures thereof.Such matrix materials, have been used with faujasite type catalysts inthe prior art and are useful additives with the treated gels of ourinvention. The art of incorporating matrix materials with activecatalysts, such as for example zeolites, is well known and such matrixcompositions may be employed with the treated cogels of our invention.

The cogel, which we prefer to treat by the process of our invention toform the catalyst of our invention may be produced by any of the methodsused in the prior art to form such cogels in which the treatment resultsin a gel having an ammonium ion associated with gel as in the ammoniatedgel referred to above.

The cogel, which may be hydrothermally treated according to ourinvention, may be formed by treating a mixture of silica hydrosol withaluminum salt in the ratios to produce a gel of the desires SiO₂ /Al₂ O₃ratio and exchanged with ammonium cation to reduce the sodium content ofthe gel.

We prefer to coprecipitate the silica-alumina hydrosol to form the gelfrom a mixture of sodium silicate and aluminum salt, e.g. aluminumsulfate, or aluminum nitrate or aluminum chloride made alkaline withammonium hydroxide to reduce the sodium content as is more fullydescribed below.

We have found that the improvement in the catalytic activity of a geltreated according to our invention depends on the silica to aluminaratio of the cogel. The ammonia content of the ammoniated gel of ourinvention depends on the silica to alumina ratio of the gel. Thecatalytic activity attainable by our invention is substantially greateras the molar weight ratio of SiO₂ to Al₂ O₃ is less than about 3 andpreferably about 1 to about 2.

Our preferred embodiment of our invention is to employ an ammoniatedsilica-alumina cogel having an SiO₂ /Al₂ O₃ molar ratio in the range ofabout 1.25 to about 2.5, and an ammonium ion content of less than about0.3 equivalents of ammonium cation per mole of Al₂ O₃ to form a catalysthaving an M activity in excess of 60%.

The preferred embodiment of the process for producing the preferredembodiment of the cogel crystalline zeolite of our invention is tohydrothermally treat an ammoniated cogel with an acid solution of rareearth cations at an elevated temperature to reduce the ammonia contentof the gel as stated above. While we have found that the reactionconditions which produce an exchanged cogel of low ammonium content andwhich has a high M activity may also contain a crystalline phase ofcharacteristic x-ray spectrum, gels which are produced under milderconditions may also be amorphous and have superior M and S+ activities.

The activity of the catalyst of our invention may be measured by themicroactivity cracking test described in the Oil and Gas Journal ofSept. 16, 1966; page 48, etc., and Nov. 22, 1975; page 60, etc.

In the following examples the conditions in carrying our the above testsis as follows. The calcined pelleted catalyst was first steamed attemperatures and for times specified below and then used in cracking ofa petroleum fraction under the following conditions. The oil charge isalkali metal cation, or exchanged with a polyvalent cation, may beencapsulated in the cogel by mixing the zeolite with the gel formingingredients. The mixture may then be hydrothermally treated to reducethe sodium content according to the process of our invention.

The mixture of zeolite and hydrothermally treated gel may besupplemented by a matrix material such as has been used in the prior artin connection with zeolite catalysts, for example clay, such as kaolinclays, inorganic oxides, such as silica, or silica-alumina, orsilica-alumina gels.

Examples 1 and 2 illustrate our prefered cogels.

EXAMPLE 1

5,017 grams of sodium silicate (28% SiO₂ +8.9% Na₂ O by weight)equivalent to 1,440 grams of SiO₂ is dissolved in water. The solution isacidified to a pH of 11 with sulfuric acid. 26,896 grams of an aluminumsulfate solution (equivalent to 1,560 grams of Al₂ O₃) is addedgradually to the acidified slurry with constant agitation. The pH at theend of the addition of the aluminum sulfate should be in the range ofabout 3 to about 3.5. The solution is passed through a colloid mill tobe well homogenized. The homogenized solution is made alkaline withammonium hydroxide with constant and vigorous agitation to adjust themixture to a pH of about 8.5 to about 9.

The mixture is vigorously stirred and the pH is maintained in the rangeof about 8.5 to about 9 by suitable adjustment for about 1 hour toinsure uniformity of the mixture. It is then heated to a temperature ofabout 75° to 80° C. The washed filter cake is then slurried to a solidcontent of about 5% in distilled water which contained about 2% ofammonium nitrate and then filtered. The filter cake is then againslurried with ammonium nitrate solution as in the last previous step.The filter cake from the last step is again reslurried in an ammoniumnitrate solution as above and filtered. The filter cake from the lastfiltration above is washed with distilled water.

The silica-alumina hydrogel thus produced is preferably maintained in asealed container prior to use in the catalyst of our invention. Itshould be used as promptly as possible since aging of the gel willimpair its properties in producing a good attrition resistant catalyst.

The gel produced as in Example 1 analyzed on a volatile free basis asfollows:

SiO₂ =48.7% by weight

Al₂ O₃ =51.1% by weight

Na₂ O=0.27% by weight

NH₃ =3.67% by weight

This corresponds to 0.44 equivalents of NH₄ per mole of Al₂ O₃. The SiO₂/Al₂ O₃ molar ratio is 1.62.

The pore volume, the distribution of the pore volume according to theirdiameters and the surface area of the gel were determined (see J.A.C.S.[1938] Vol., p. 309, etc.):

Surface area (M² /gram) equals 0.712;

Total pore volume (cc/gram) equals 0.67;

Surface area in pores of 30 to 600 Angstroms diameters equals 457 M²/grams;

Pore volume of pores of 30 to 600 Angstroms diameters equals 0.51cc/gram;

Percent of pore volume as percent of the volume in poures of 30 to 600 A(Angstroms) equals:

300 to 600 A=0.1

200 to 300 A=0.1

100 to 200 A=0.6

50 to 100 A=11.2

30 to 50 A=88

Pore volume distribution as percent in pores of 10 to 300 Angstromsradius pores:

    ______________________________________                                        Pore Radius         Percent                                                   ______________________________________                                        200 to 300 A      =     0                                                     150 to 200 A      =     0                                                     100 to 150 A      =     0                                                      50 to 100 A      =     .1                                                     25 to  50 A      =     9.7                                                    10 to  20 A      =     89.6                                                  ______________________________________                                    

The ammoniated cogel is amorphous to K alpha copper radiation at 500counts per second on the counter of the strip chart x-ray apparatus. Itshowed no discernable peaks in the x-ray spectrum so produced. The gelproduced as above, was employed in the following examples, except inExample 19 where the acid gel was used. In all examples and except as isindicated in Example 7, where zerogel was employed, all of the examplesemployed the hydrogel.

The above cogel was pelleted and tested by the microcativity testidentified above after steaming at 1450° F. for two hours (M activity)and again another sample after steaming at 1500° F. for two hours (Sactivity) and a third sample after steaming for 2 hours at 1550° F. (S+activity). The results are reported as volume percent conversion.

The results obtained were as follows:

    ______________________________________                                                         M     S        S+                                            ______________________________________                                        Volume % conversion:                                                                             43      36.5     46                                        ______________________________________                                    

The gel was also mixed with acid treated halloysite (see Secor; U.S.Pat. Nos. 2,935,463, and 3,446,727) in the ratio of 90% by weight of thedried gel and 10% by weight of the dry halloysite. The mixture wastested as above with the following results:

    ______________________________________                                                          M       S+                                                  ______________________________________                                        Volume % conversion 47        44                                              ______________________________________                                    

EXAMPLE 2

The procedure of Example 1 was used to form the cogel, but instead ofaluminum sulfate, an equivalent amount of Al₂ O₃, an equivalent amountof aluminum nitrate and sodium aluminate in ratio to give 75% of the Al₂O₃ to come from sodium aluminate (NaAlO₂) and 25% from the aluminumnitrate. The gel was analyzed with the following results on a volatilefree basis:

SiO₂ =49.6%

Al₂ O₃ =49.8%

Na₂ O=0.13%

NH₃ =2.40%

The SiO₂ /Al₂ O₃ molar ratio is 1.69.

Surface area M² /gram equals 708;

Pore Volume cc/gram equals 0.84;

Surface area in pores of 30 to 600 Angstroms diameter equals 482 M²/gram;

Pore volume in pores of 30 to 600 Angstroms diameters equal 017 cc/gram;

Pore volume distributuion and percent of pore volume in pores of 30 to600 Angstroms diameter;

300 to 600 A equals 0.5%

200 to 100 A equals 0.6%

100 to 200 A. equals 7.9%

50 to 100 A equals 50.5%

30 to 50 A equals 40.5%;

Pore volume distribution as percent of pore volume in pores of:

200 to 300 A. equals 0.3%

150 to 200 A equals 0.2%

100 to 150 A. equals 0.5%

50 to 100 A equals 6.0%

25 to 50 A equals 44.6%

10 to 25 A equals 47.5%;

The pore volume is more uniformly distributed between the pores of 30 to100 Angstrom diameters in comparison with those of the gels of Example1.

EXAMPLE 3

300 grams (on a volatile free basis) of the silica-alumina gel producedas in Example 1 was mixed with a solution of rare earth sulfate,equivalent to 75 grams of ReO in water to form a slurry containing about6% of solids. The composition of the rare earth sulfate expressed asoxides and symbolized as ReO was:

La₂ O₃ =57% by weight

CeO₂ =16% by weight

Nd₂ O₃ =21% by weight

Other rare earth oxides=7% by weight

100 grams of ReO (volatile free) is equal to 1.896 equivalents of ReO,i.e., 52.7 grams per equivalent.

The ReO was determined by the standard oxalate method. See Roden,"Analytical Chemistry of the Manhatten Project", McGraw-Hill Co.,Chapter 22. In all examples ReO was similarly determined and had theabove equivalent value.

The above mixture was held at the temperature of about 180° to 200° F.for about two hours at atmospheric pressure. During the reactions, thepH of the mixture was adjusted to hold a pH in the range of 5.2 to 5.4.

The mixture was filtered and washed. A sample of the filter cake wasanalyzed on a volatile free basis as follows. The filter cake wasanalyzed:

SiO₂ =43.7% by weight

Al₂ O₃ =46.3% by weight

Na₂ O=0.64% by weight

ReO=10.2% by weight

NH₃ =1.25% by weight

SO₃ =0.83% by weight

The ratio of equivalents of NH₄ per mole of Al₂ O₃ is 0.16 and the ratioof the equivalents of ReO per mole of Al₂ O₃ is 0.43.

It was amorphous as in the case of the cogel of Example 1.

90% of the dried filter cake was mixed with 10% of acid treatedhalloysite as in Example 1. The mixture was tested as in Example 2 withthe following results:

    ______________________________________                                                          M       S+                                                  ______________________________________                                        Volume % conversion 62        51                                              ______________________________________                                    

EXAMPLE 4

The cogel of Example 1 (1000 grams on a volatile free basis) was mixedwith lanthanum nitrate solution in an amount to equal 100 grams of ReO(as La₂ O₃) in water and mixed for one hour at ambient temperatures andthen heated for one hour at 160° to 170° F. at a pH of 5.2 to 5.4. Theexchanged sample was filtered and washed. The washed filter cake wasdried at 250° F. for three to four hours and reexchanged as above,filtered, washed, and dried as above. The exchange as described abovewas repeated for a third time. The resultant exchanged gel contained (ona volatile free basis):

SiO₂ =47.4%

Al₂ O₃ =44.3%

La₂ O₃ =8.21%

NH₃ =1.14%

Na₂ O=0.07%

The exchanged gel was amorphous to x-ray as above. The ratio of theequivalents of NH₄ per mole of Al₂ O₃ is 0.16 and for ReO (La₂ O₃) theratio of equivalents per mole of Al₂ O₃ is 0.35.

The gel was formulated with clay as in Example 1 and tested formicroactivity by the above test, with the following results:

M=63%

S+=54%

EXAMPLE 5

300 grams (on a volatile free basis) of the cogel described in Example 1was mixed with rare earth sulfate as in Example 3, in amount equivalentto 21 grams of ReO as described above in 4,700 ml of water. The pH wasadjusted with NaOH to a pH of 8. The mixture was agitated for an hour ata temperature of 160° F. at atmospheric pressure. The slurry wasfiltered and washed until the wash water was substantially free ofsulfate ions. The filter cake was analyzed and its analysis on avolatile free weight basis was as follows:

SiO₂ =45.5% by weight

Al₂ O₃ =46.7% by weight

Na₂ O=0.23% by weight

ReO=7.18% by weight

NH₃ =2.14% by weight

SO₃ =0.23% by weight

The ratio of equivalents of NH₄ per mole of Al₂ O₃ is 0.28 and for ReO,the ratio of equivalents per mole of Al₂ O₃ is 0.3.

It was composited as in Example 1 (90% gel and 10% acid treatedhalloysite) and tested as in Example 2 with the following results:

    ______________________________________                                                         M     S        S+                                            ______________________________________                                        Volume % conversion                                                                              57      53       47                                        ______________________________________                                    

EXAMPLE 6

The gel of Example 1 was exchanged employing a lanthanum nitrate insolution, in an amount equal to 10% of the gel, both on a volatile freebasis. The mixture was held for an hour at ambient temperature at a pHof 5.2 to 5.4, and then heated at a temperature of 160° F. to 170° F.for an hour. The gel was then filtered and the filter cake was washedand dried. The exchanged gel was reslurried in water and reexchanged asdescribed above, filtered, and the filter ckae washed and dried. It wasanalyzed with the following results:

La₂ O₃ =8.34%

NH₃ =0.98%

Na₂ O=0.12%

A thousand grams of this gel (on a volatile free basis) was thenreslurried in water containing 2,500 grams of ammonium sulfate (on avolatile free basis) to a total volume of 20,000 ml. The mixture wasadjusted to a pH of 5 to 5.2 and held for one hour at ambienttemperatures, and then charged into an autoclave where it was held fortwo hours at a temperature of 400° F., filtered, washed, and analyzedwith the following results:

ReO (La₂ O₃)=trace

NH₃ =3.09%

Na₂ O=0.05%

SO₃ =4.60%

The high concentration of SO₃ indicates that it was contaminated withconsiderable ammonium sulfate, since the original ReO exchanged gel wassulfate free. The NH₃ equivalent to the SO₃ content should then besubtracted from the 3.09% of the ammonia to indicate the ammoniaremaining in the gel in exchanged position to wit equal to 0.57%. Thegel was formulated as in Example 1 and tested for activity with thefollowing results:

M=66%

S+=60%

The gel showed a small percentage of an incipient crystallinity ofindeterminate character.

EXAMPLE 7

The gel of Example 1 was dried at 400° F. and the dried mass was reducedto a powder in a hammer mill. The ammoniated xerogel product wasdispersed in ammonium sulfate solution containing 10% by weight of thesulfate based on the gel on a volatile free basis. The suspension wasdigested for thirty minutes at 160° F. The treated slurry was dried andreexchanged as above, drained, and again reexchanged as above, employingin this case 40% of ammonium sulfate based on the gel on a volatile freebasis. The gel resulting from the third exchange was filtered andwashed. It was analyzed with the following results (volatile freebasis):

NH₃ =3.32%

Na₂ O=0.2%

The sulfate contents of the filter cake was not determined.

It was amorphous as was disclosed by the x-ray pattern taken as inExample 1. The gel was formulated into a catalyst as in Example 1, andtested for activity with the following results:

M=60%

S+=52%

EXAMPLE 8

200 grams (volatile free) of the gel of Example 1 were dispersed inwater containing 200 grams (on a volatile free basis) of NH₄ NO₃ in twoliters of water. The pH of the dispersion was adjusted to a pH of about4 to about 4.5 and heated for two hours at 160° F. The gel was filteredand washed until the wash water appeared nitrate free. The exchanged gelwas analyzed for NH₃. The NH₃ content of the filter cake was 3.4 on avolatile free basis. The nitrate content of the filter cake was notdetermined.

The x-ray spectrum obtained as described in Example 1 showed a smallpercentage of an incipient crystallinity of undeterminatecharacteristics. The x-ray spectrum showed peaks whose d spacingscorrespond to an average a_(o) of 25.48 angstroms. (See in thisconnection our copending application, Ser. No. 003,879 now U.S. Pat. No.4,238,360,.)

It was combined with the acid treated clay as in Example 1 and testedfor M microactivity. The activity was:

Volume % conversion=58%

EXAMPLE 9

The cogel prepared as in Example 1 was heated to 600° to 700° F., andsteamed at a temperature of about 1200° F. was passed over the heatedcogel for three hours. The cooled cogel was then treated with rare earthas in Example 3. The steamed gel after treatment with the rare earthsulfate was filtered and the filter cake was washed, as in Example 3. Ithad the following compositions by weight on a volatile free basis:

SiO₂ =46.4% by weight

Al₂ O₃ =50.8% by weight

Na₂ O=0.20% by weight

ReO=2.09% by weight

NH₃ =1.05% by weight

SO₃ =0.48% by weight

The ratio of the equivalents of NH₄ per mole fo Al₂ O₃ is 0.12, and forReO the ratio of equivalents per mole of Al₂ O₃ is 0.1.

The treated cogel was mixed with acid treated halloysite as in Example 1(90% cogel and 10% halloysite) and tested as in Example 1 with thefollowing results:

    ______________________________________                                                         M     S        S+                                            ______________________________________                                        Volume % conversion                                                                              66      52       51                                        ______________________________________                                    

EXAMPLE 10

1,600 grams of the cogel prepared as in Example 1 (calculated on avolatile free basis) was mixed gradually with 18.4 liters of a rareearth sulfate solution containing 1.96% ReO (23% by weight of the gel)while the mixture was maintained for about an hour at a pH of 5 byadjustment during the mixing. The above slurry was then introduced intoan autoclave and heated at a temperature of 400° F. for about two hours.The mixture was then cooled and filtered. The filter cake was washeduntil the wash water appeared substantially free of sulfate ions. Thefilter cake analyzed on a volatile free basis as follows:

SiO₂ =45.6% by weight

Al₂ O₃ =48.8% by weight

Na₂ O=0.06% by weight

ReO=4.15% by weight

NH₃ =0.3% by weight

SO₃ =0.67% by weight

The ratio of equivalents of NH₃ per mole of Al₂ O₃ is 0.04, and for ReO,the ratio of equivalents per mole of Al₂ O₃ is 0.13.

The filter cake was x-rayed as in Example 1 and the "d" spacings andintensities (I) of the corresponding lines measured as the height of thepeaks on the strip chart were determined.

                  TABLE 1                                                         ______________________________________                                        d                 I                                                           ______________________________________                                        6.39              6                                                           6.26              24                                                          4.58              3                                                           3.57              3                                                           3.49              3                                                           3.41              2                                                           3.24              2                                                           3.14              3                                                           3.00              10                                                          2.86              3                                                           2.43              2                                                           2.21              6                                                           ______________________________________                                    

The cogel treated as above was slurried in water with 10% of acidtreated halloysite and 90% of the cogel all measured on a volatile freebasis as in Example 1 and subjected to the above test as set forth inExample 1 with the following results:

    ______________________________________                                                         M     S        S+                                            ______________________________________                                        Volume % conversion                                                                              77      62       56                                        ______________________________________                                    

EXAMPLE 11

The preparation of Example 10 was carried out as described but insteadof rare earth sulfate, ammonium sulfate was employed.

1200 grams (on a volatile free basis) was added gradually to 12,000 ccof water containing 3,000 grams of (NH₄)₂ SO₄ (on a volatile freebasis). The pH was adjusted during addition to a pH of 5.5. The slurrywas autoclaved for two hours at 400° F., cooled and filtered. The filtercake was washed until the wash water was substantially free of sulfateions.

The gel was analyzed on a volatile free basis:

SiO₂ =48.2% by weight

Al₂ O₃ =51.3% by weight

Na₂ O=0.10% by weight

NH₃ =2.43% by weight

SO₃ =0.99% by weight

Since the SO₃ is introduced by the ammonium sulfate, the net NH₃ + inexchange position is equal to 2.0% after subtracting the NH₃ equivalentto the SO₃. This corresponds to 0.24 equivalents of NH₄ per mole of Al₂O₃.

90% of the gel was mixed with 10% of acid treated halloysite as aboveand tested as in Example 1.

    ______________________________________                                                         M     S        S+                                            ______________________________________                                        Volume % conversion                                                                              63      59       58                                        ______________________________________                                    

It will be noted that notwithstanding the presence of about 55equivalents of NH₄ + per liter, the treatment resulted in a reduction ofthe NH₄ content from 3.67% in the ammoniated gel of Example 1 to 2.0% inthe treated gel.

EXAMPLE 12

The procedure of Example 10 was repeated except that the ReO was used inthe ratio of 10% by weight of the gel. The exchanged gel had thefollowing composition:

SiO₂ =44%

Al₂ O₃ =47.6%

ReO=6.81%

NH₃ =0.75%

Na₂ O=0.06%

This corresponds to a ratio of equivalents of NH₄ per mole of Al₂ O₃ of0.09 and of ReO the ratio of equivalents per mole of Al₂ O₃ is 0.27.

Examined by x-ray as in Example 1, the pattern showed that the gelcontained a crystalline phase substantially different from the productof Example 10.

The following Table 2 states the "d" spacings of the reflections.

                  TABLE 2                                                         ______________________________________                                        d (Angstroms)       I                                                         ______________________________________                                        8.44                44                                                        4.75                4                                                         4.47                5                                                         4.24                4                                                         4.16                3                                                         3.96                3                                                         3.76                3                                                         3.26                4                                                         3.04                3                                                         2.33                2                                                         ______________________________________                                    

The exchanged gel when formulated as in Example 1 had the followingresults:

M=68.4%

S+=61.6%

EXAMPLE 13

In this example, the gel as in Example 1 was exchanged with magnesiumnitrate as a pH of 4 under autogenous pressure at a temperature of 400°F. for two hours, cooled, filtered and washed. The filter cake wasanalyzed and had the following composition on a volatile free basis:

Al₂ O₃ =50.4% by weight

SiO₂ =46.9% by weight

Na₂ O=0.09% by weight

NH₃ =0.88% by weight

MgO=0.56% by weight

NO₃ =0.64% by weight

This corresponds to 0.06 equivalents of NH₄ per mole of Al₂ O₃.

The x-ray pattern produced as in Example 1 showed the followingreflections reported as "d" spacings.

                  TABLE 3                                                         ______________________________________                                        d (Angstroms)       I                                                         ______________________________________                                        7.22                7                                                         4.43                5                                                         4.28                2                                                         3.61                3                                                         3.56                3                                                         3.35                14                                                        2.56                2                                                         2.35                5                                                         ______________________________________                                    

90% of the gel was mixed with 10% acid treated halloysite and tested asin Example 1 with the following results:

M=56%

S+=45%

EXAMPLE 14

50 grams of the gel of Example 1 were mixed with 1,000 ml of deionizedwater. The mixture had a pH of about 5.5 and was heated under pressureat a temperature of 400° F., for two hours, cooled and filtered. Thefiltrate contained ammonium ions equivalent to 0.374 grams of NH₃ perliter. This indicates that the pH was raised to the equivalent value,i.e., substantially to neutrality.

The gel was analyzed and found to have lost about a quarter of itsammonium. The x-ray spectrum obtained as in Example 1 showed that thetreated gel was amorphous. It was formulated as in Example 1 and had anM activity of 48% and S+ activity of 37%.

The following examples indicate that the hydrothermal treatment may becarried on for too long a time or an excessively high temperature orboth with disadvantageous effect on the catalytic activity of theresultant catalyst. This effect may occur in the case where theresultant gel is either amorphous or contains a crystalline phase. Inthe latter, the crystallinity is of a different character from the moremildly treated ammoniated gel.

EXAMPLE 15

Example 10 was repeated but the temperature was adjusted to 500° F., andthe ReO was employed in a ratio of 33% of the gel on a volatile freebasis, and the digestion was carried on for eight (8) hours and anotherfor twenty-four (24) hours.

The exchanged gel was analyzed with the following results:

    ______________________________________                                                       SAMPLE                                                                        1      2                                                                      8 hours                                                                              24 hours                                                ______________________________________                                        SiO.sub.2   =        40.6%    44.6%                                           Al.sub.2 O.sub.3                                                                          =        44.3%    45.2%                                           ReO         =        8.53%    9.08%                                           NH.sub.3    =        0.55%    1.17%                                           Na.sub.2 O  =        0.83%    0.17%                                           ______________________________________                                    

The ratio of equivalents of NH₄ per mole of Al₂ O₃ for Sample 1 is 0.07,and for Sample 2, it is 0.16; for ReO for Sample 1, the ratio ofequivalents per mole of Al₂ O₃ is 0.38, and for Sample 2, it is 0.39.

The x-ray pattern obtained as in Example 1 showed a d spacing whichcorresponds for Sample 1 to an average a_(o) of 25.40 Angstroms and forSample 2, an average a_(o) of 24.56 Angstroms (see our application Ser.No. 003,879 now U.S. Pat. No. 4,238,360;).

Formulates as in Example 1, the activity of the catalyst was:

    ______________________________________                                                    Sample 1                                                                             Sample 2                                                   ______________________________________                                        M             53       41.4                                                   S+            46.4     43.1                                                   ______________________________________                                    

EXAMPLE 16

The gel of Example 1 was that exchanged using rare earth sulfate ofExample 3 equal to 10% of the weight of the gel on a volatile freebasis, and the digestion was carried out for twenty-four (24) hours at212° F. The resultant washed gel had the following composition:

SiO₂ =48.7%

Al₂ O₃ =40.9%

ReO=7.7%

NH₃ =0.60%

SO₃ =0.81%

The corresponding equivaltent of NH₄ per mole of Al₂ O₃ is 0.1 and forReO the equivalent ratio per mole of Al₂ O₃ is 0.37.

It was amorphous to x-ray as above. The gel was tested for microactivitywith the following results:

M=45.6%

S+=42.0%

EXAMPLE 17

A gel formed as in Example 1 was exchanged with ammonium nitrate at atemperature of about 160° F. to 170° F. for one (1) hour. The pH wasadjusted during the exchange with ammonium hydroxide to hold the pH in arange of 5 to 5.2. The mixture was filtered and dried and reexchanged asabove. The washed filter cake was exchanged with lanthanum chloride at250° F. for two (2) hours at a pH of 5 to 5.2. The exchanged zeolite wasfiltered and washed.

The filter cake analyzed as follows, on a volatile free basis:

SiO₂ =48.1%

Al₂ O₃ =42.8%

Na₂ O=0.027%

NH₃ =1.95%

La₂ O₃ =7.74%

The ratio of equivalents of NH₄ per mole of Al₂ O₃ is 0.26, and theratio of equivalents of La₂ O₃ per mole of Al₂ O₃ is 0.31.

The exchanged gel was amorphous to x-ray as in the case of Example 1.The exchanged zeolite was mixed with acid treated clay as in Example 1and tested for microactivity with the following results:

M=64%

S+=55%

EXAMPLE 18

A gel formed as in Example 2 was exchanged with rare earth sulfate at atemperature of 200° F. for three (3) hours and then filtered. Thefiltrate had a pH of 5.5. The filter cake was washed. A similar secondexchange was for three (3) hours and the third similar exchange was fortwo and a half (21/2) hours, both at pH adjusted to 5.1 to 5.3. Thewashed filter cake from the third exchange was analyzed as follows, on avolatile free basis:

SiO₂ =50.0%

Al₂ O₃ =45.8%

Na₂ O=0.14%

ReO=4.20%

NH₃ =0.30%

The ratio of equivalents of NH₄ per mole of Al₂ O₃ is 0.24 and for ReOthe ratio of equivalents per mole of Al₂ O₃ is 0.18.

The exchanged gel was amorphous to x-ray as in Example 1. The filtercake was formulated as in Example 1 and tested for activity with thefollowing results:

M=67%

S+=55%

EXAMPLE 19

In this example an acid gel was employed instead of an ammoniated gel.

Sodium silicate in an amount equivalent to 480 grams of SiO₂ (volatilefree) and 520 grams of Al₂ O₃ (volatile free) as aluminum sulfate weremixed in water so as to establish a gel (5% solids), i.e. SiO₂ /Al₂ O₃molar ratio of 1.6. They were thoroughly mixed. The pH during mixing wasadjusted to a pH at about 6.5 by the addition of sulfuric acid. Themixture was heated to about 160° F. for an hour and filtered and washeduntil the wash water was substantially free of sulfate ions.

The washed gel was exchanged employed a ratio of ReO to gel of 33 gramsof ReO as rare earth salt per hundred grams of the gel (on a volatilefree basis). The mixture was adjusted with acid to a pH of about 5thoroughly mixed for about an hour and introduced into an autoclave andheated for two hours at 400° F. It was then cooled and filtered and thefilter cake washed thoroughly. The exchanged gel analyzed on a volatilefree basis as follows:

Na₂ O=0.007%

ReO=nil

NH₄ =nil

The filter cake was combined with clay as in Example 1 and tested formicroactivity with the following results:

M=67.5%

S+=48.7%

The treated gel showed no crystal structure by the x-ray examination asin Example 1. It was amorphous.

The following examples illustrate the effect of the SiO₂ /Al₂ O₃ molarratio of the ammoniated gel on its activity.

EXAMPLE 20

A gel prepared according to the procedure of Example 1, with thesilicate and aluminum salt adjusted in composition to give the followingSiO₂ /Al₂ O₃ ratio. It was analyzed as in Example 1, and had thefollowing composition:

SiO₂ =25.0% by weight

Al₂ O₃ =74.2% by weight

Na₂ O=0.033% by weight

NH₃ =0.25% by weight

The SiO₂ /Al₂ O₃ molar ratio is 0.57.

It was formulated and tested as in Example 1, with the followingresults:

M=55%

S+=51.7%

The gel of Example 20 wax exchanged under pressure and processed as inExample 10. It analyzed as follows:

ReO=0.15% by weight

NH₃ =0.24% by weight

It was formulated with a catalyst and tested as in Example 1 with thefollowing result:

M=53% by weight

EXAMPLE 21

Another gel was formed as in Example 1, but the ratio of the reactantswas adjusted to produce a gel containing 75% SiO₂ and 25% Al₂ O₃ byweight.

The resultant gel analyzed as follows:

SiO₂ =73.0% by weight

Al₂ O₃ =26.3% by weight

Na₂ O=0.08% by weight

NH₃ =1.06% by weight

The SiO₂ /Al₂ O₃ molar ratio is 4.72.

EXAMPLE 22

The ammoniated gel which we prefer to employ has a SiO₂ /Al₂ O₃ ratio inthe range of about 1 to about 3. Ammoniated gels which have SiO₂ /Al₂ O₃ratio substantially outside this range do not on deammoniation by theprocess of our invention attanin an activities which is obtainable whenemploying the preferred gels.

It will be seen that the reduction in the content of ammonium cation bythe hydrolytic exchange was accompanied by a substantial increase inactivity. The activity appears to be a funtion of the ammonium contentof the exchanged gel. The lower the equivalents of NH₄ (reported as NH₃)per mole of Al₂ O₃ the higher the M and S+ activity.

The level of activity depends to some estent on the cations employed.Thus compare the exchange with magnesium cation of Example 13 withExample 12 where the exchange was with an acid solution of rare earthsalts. The magnesium salt, where the deammoniation was the greater thanwith the rare earth salt, the improvement in activity achieved by theexchange with magnesium ion yielded an M of 56% and an S+ of 45%,compared with M of 68% and an S+ of 62% for Example 12.

We prefer to employ the rare earth cations under acid conditions. Whilesome appreciateion in activity is obtained when using the rare earthsalts under mild alkaline conditions, the appreciateion in activity isnot obtained for like amount of deammoniation. Compare Example 5 withExample 17.

In employing rare earth surfate for the exchange salt in the hydrolytictreatment of the gel, the improvement in activity obtained by thedeammoniation may be depreciated if the temperature or the time ofdigestion or both are made excessive.

While we do not wish to be bound by any theory of why the facts are asobserved, the data tend to indicate that the hydrolytically treated gelforms, whether it be a crystalline or amorphous, a catalytically activestructure which is a metastable form. Continued treatment or excessivetemperature transforms the gel and depreciates its activity.

Those skilled in the art will understand from the above disclosure howto determine temperatures, times, cation selection, and concentration toobtain the desired level of activity. The examples illustrate theprocedure and result effective parameters and may act as a guide tothose who wish to determine these parameters for their particularconditions and desired result.

The following example illustrates the qualities of the catalystsproduced by a combination of the hydrothermally treated gel of ourinvention with a crystalline alumino-silicate faujasite zeolite. Suchnovel composite catalysts have a superior hydrothermal stability andcatalytic activity to produce a high octane gasoline.

Example 21 illustrates the excellent activity of the mixture of the rareearth exchanged alumina-silica gel of our invention in a mixture with afaujasite type zeolite.

It is our presently preferred embodiment of our invention when thehydrothermally treated gel is employed in combination with a faujasite.

EXAMPLE 23

A Na Y zeolite having an SiO₂ /Al₂ O₃ ratio of 4.74 was dispersed inwater and acidified with sulfuric acid to a pH of about 3.5. Theresultant slurry was heated to a temperature of 160° F. to 180° F. witha rare earth salt solution employing the rare earth sulfate of Example10.

The washed filter cake of the above slurry was analyzed and contained10.8% ReO and 3.8% Na₂ O on a volatile free basis. The 19% of theexchanged zeolite 47% ball clay when formulated with 16% acid treatedhalloysite and 18% pseudoboehmite in a slurry and spray dried and testedby the above microactivity test with the following results:

M=73%

S+=30%

A portion of the above filter cake was mixed with the washed filter cakeof the exchanged silica-alumina gel of Example 10 in the ratio to give10% rare earth exchanged Y zeolite and 90% of the exchanged gel on avolatile free basis. The slurry of the mixed filter cakes was dried.

The resultant catalyst containing the zeolite and gel was tested by theabove microactivity test with the following results:

M=83%

S+=73%

This activity may be compared with that of the catalyst referred topreviously in this Example 23. The spray dried slurry of the mixedfilter cake as above, was tested by the fluid cracking test.

A test oil (ASTM Subcommitted D32, Standard FHC 893) is vaporized andpassed through a bed of microspheres produced by the above spray dryingof the mixed filter cakes. Spray dried microspheres are of a particlesize within the range of 50 to 70 microns.

In the particular test, the catalyst charge was 4.00±0.05 grams and2.33±0.03 grams of oil was passed through the catalyst bed over a periodof 75 seconds. The catalyst was prepared by heating a shallow bed of thecatalyst for three hours in air at 1050° F. and then steamed as in theabove microactivity test at 1450° F. for two (2) hours and anothersample was steamed at 1550° F. for two (2) hours. The oil passed througha preheat zone and through a bed of the microspheres maintained at atemperature of 900° F.±2° F. at a weight hourly space velocity (WHSV) of16.

    WHSV=1.33/4×3600/75=16

The vapors and gases passing from the bed are condensed in an ice bathand the uncondensed gases collected over water.

The following observations are made. The weight of the condensate andthe volume and temperature of the gases are determined. The liquidcondensate fraction is analyzed and the percent by weight of the liquidfraction which boiled above 421° F. and the fraction of the liquidcondensate boiling below 421° F. is determined. The volume andtemperature of the gases collected over the water are measured and thevolume reduced to standard conditions. The uncondensed gases areanalyzed and the weight percent of the gases which is hydrogen,isopentane, and hexane is determined and their weight percent of thefeed determined. The weight percent conversion of the liquid charge isdetermined from the following relation:

F is the weight in grams of the oil passing through the reactor;

L is the weight in grams of the liquid product which is collected ascondensate;

R is the percent by weight in grmas of the fraction of the liquidcondensate which boils above 421° F.;

H is the grams of liquid held up in the reactor exit line and around thereactor, receiver, and joints.

In the above test it has been determined that H constitutes threepercent of the feed F. The weight percent conversion (%C) is given bythe following relationship. ##EQU1##

The weight percent of the gasoline is given by the sum of the percent bythe weight to the fraction boiling below 421° F. and the weight percentof the isopentane and hexand.

The coke which is deposited on the catalyst is obtained by burning thecoke off of the catalyst remaining after the test and the weight ofcarbon deposited is determined from the CO₂ generated. The weightpercent of the feed which appears as carbon is thus determined.

The spray dried microspheres which were heated with steam at 1450° F.and another sample which was heated at 1550° F. each for two (2) hoursas above, were each tested by the above test with the following results:

    ______________________________________                                             Conversion                                                               °F.                                                                         Wt. %     Gasoline %                                                                              Coke % Hydrogen                                                                              Isobutane                             ______________________________________                                        1450°                                                                       72.7%     45.4%     6.60%  .077    5.18                                  1550°                                                                       57.1%     36.51%    5.73%  .082    2.29                                  ______________________________________                                    

The gasoline had a 90.6 octane value according to the test proceduredescribed in: Anderson, et al. "Calculation of the Research OctaneNumber of Motor Gasoline from Gas Chromatograph Data and a New Approachto Motor Gasoline Quality Control", Journal of the Institute ofPetroleum, Vol. 53, March 1972, pp. 83-94.

When using the above exchanged ammoniated gel with a zeolite, we preferto use the exchanged gel mixed with the rare earth exchanged zeolites ofthe prior art with an Na₂ O content of less than about 4-5%, for example3.5% and preferably the so-called A type (see U.S. Pat. No. 4,100,108);we prefer to employ the Y zeolite of an SiO₂ /Al₂ O₃ ratio of above 4,for example, 4.5. The percent of the zeolites and the gel on a volatilefree basis may be about 5% to 25% of the mixture, the exchanged gel.

Our invention relates to a process of the combining of a CAS zeolitewith a hydrolytically treated silica-alumina cogel. The hydrolytictreatment may be that of acid silica-alumina gels or ammoniatedsilica-alumina gels of low sodium content. The gels in the combinationhave a weight ratio in the range of less than about 1% expressed as Na₂O and having an SiO₂ /Al₂ O₃ mole ratio less than 4 and preferably inthe range of about 1 to about 3. In the case of the ammoniated gels,containing NH₄ cations associated with the gel in amount expressed asequivalents of NH₄ per mole of Al₂ O₃ in excess of about 0.3 to reducethe content of NH₄ ⁺ to substantially less than about 0.3 equivalentsper mole of Al₂ O₃.

The preferred embodiment of our invention includes the treatment of anammoniated gel with rare earth cations under acid conditions attemperatures above about 150° F. for a time to reduce the NH₄ ioncontent in the gel to less than about 0.15 equivalents of NH₄ per moleof Al₂ O₃ and to employ for such purposes a cogel with a SiO₂ /Al₂ O₃molar ratio substantially more than 1 and less than 3 and itscombination with a suitable CAS zeolite.

For purposes of maintaining the treated product in an amorphouscondition, we prefer to maintain the temperature from about 150° F. tothe boiling point under atmospheric conditions.

For purposes of generating a crystalline phase in the gel forcombination with a CAS zeolite, we prefer to carry out the hydrothermaltreatment under autogenous pressure at temperatures up to about 450° F.,i.e. 225° F. to about 450° F.

The time of digestion is controlled so as not to be excessive asdescribed above. The time of digestion may be from about one (1) hour toabout two (2) to four (4) hours at the above temperatures.

The above procedures for reducing the NH₄ content of the ammoniated gelmay be employed in combination. Thus the ammoniated gel of Example 1 maybe exchanged at atomospheric pressure and reexchanged one or more timesin multiple steps. The atmospheric exchanged gel of Example 3 may bereexchanged under pressure under similar procedures as in Example 6. Theexchanged gel of Example 3 may be steamed as in Example 5 and exchangedas in Example 5.

Our invention also relates to the combination of a CAS zeolite and asilica-alumina cogel having an SiO₂ /Al₂ O₃ ratio of less than 4preferably in the range of about 1 to about 3 which have been producedby the process of our invention.

The preferred gel is one which has a silica-alumina mole ratio of morethan about 1 and up to about 2 and a NH₄ content of less than about 0.15equivalents per mole of Al₂ O₃ and rare earth cations of about 0.5 toabout 5 equivalents per mole of Al₂ O₃.

Instead of employing the exchange zeolite and the hydrothermally treatedgel as in Example 23 the sodium CAS zeolite, for example the rare earthexchanged Y of Example 23 is mixed with the slurry of the washedfiltered ammoniated gel of Example 1 or Example 2 in a ratio of about20% of the zeolite to about 80% of the gel on a volatile free basis. Themixture is digested as in Examples 3 through 22, either with ammoniumsulfate or rare earth salts to reduce the sodium content of the CAS,preferably to less than 2% expressed as Na₂ O based on the zeolite on avolatile free basis.

Preferably we carry out the exchange of the mixed CAS zeolite and cogelunder superatmospheric pressure and pouring rare earth cations attemperatures of about 250° F. to 450° F. to reduce the sodium content ofthe CAS to less than about 2% (expressed as Na₂ O), and preferably lessthan 1% based on the CAS zeolite in the mixture on a volatile free basisand to reduce the ammonium content to less than 0.2 equivalents of NH₄per mole of Al₂ O₃ based on the gel in the catalyst. For the purposes ofthis calculation, the silica to alumina ratio of the CAS zeolite and thezeolite content of the mixture and the silica to alumina ratio of thegel and its percent in the mixture is taken on a nominal basis asestablished by the above mixture prior to hydrothermal treatment.

The treated mixture of exchanged crystalline alumino-silicate zeoliteand the exchanged gel is washed until the wash water is substantiallyfree of the anion used in the exchange process and the washed filtercake is spray dried.

An alternative procedure, according to our invention, is to combine thesodium containing CAS zeolite, for example Na Y with the ingredientsused to form the alumina/silica cogel and to exchange the mixture with asolution containing a cation other than an alkali metal cation. Thus,the process of Example 1 or Example 2 may be carried out by mixing thegel forming ingredients with the CAS solution. The mixture may be madealkaline with ammonium hydroxide as in Example 1.

The encapsulated gel zeolite thus formed, may be further exchanged withammonium salt filtered and washed. The wash slurry may then behydrothermally treated as in Example 3-21.

Preferably the exchange is carried out under superatmospheric conditionsat a temperature of about 250° F. to 450° F. with a rare earth saltsolution to reduce the sodium content (expressed as Na₂ O) to less thanabout 2% based on the zeolite on a volatile free basis and an NH₄content of less than 0.2 equivalents of NH₄ per Al₂ O₃ of the originalgel as above.

The above gel-zeolite combination may be combined with other matrixmaterials such as in ratio to include from about 5 to about 30% of thezeolite and from about 20 to about 50% of the gel, treated as above, theremaining portion may be clays and other inorganic oxides such as havebeen employed in catalysts employing CAS zeolites.

The gel-zeolite combination prior to exchange or after partial exchangeof the zeolite or zeolite gel combination may be spray dried and thespray dried microspheres further exchanged according to the proceduresof Example 3-21.

The catalyst may be employed not only as cracking catlysts to producegasoline of a superior octane, but may be used in other hydrocarbonconversion processes, such as hydroforming, hydrocracking,hydrodisulfurizing processes, for which zeolite catalysts or a silicagelcatalysts have been employed in the prior art. In this connection thezeolite-gel combination of our invention may be promoted by addition ofmetal or metallic oxides or sulfides or other compounds employed topromote the activity of crystalline zeolites or gel catalysts for suchpurposes.

We claim:
 1. The process of producing a cracking catalyst whichcomprises forming an ammoniated silica-alumina gel having an SiO₂ /Al₂O₃ molar ratio of more than about one and less than about 3 andassociated with sodium ions expressed as Na₂ O of substantially lessthan about 1% based on the gel on a volatile free basis, mixing the samewith a crystalline alumino silicate, and treating said ammoniated geland said crystalline alumino silicate by heating said mixture in asolution containing monovalent cations other than alkali metal cations,or polyvalent cations, or both said cations and separating said mixtureof said gel and crystalline alumino silicate.
 2. A process for producingan active cracking catalyst which comprises mixing a crystallinealumino-silicate zeolite having a sodium content expressed as Na₂ O,substantially more than 5% by weight of the zeolite on a volatile freebasis, with an ammoniated silica-alumina gel containing NH₄ ionsassociated with the gel in an amount, substantially in excess of about0.3 equivalents per mole of alumina (Al₂ O₃), and having an SiO₂ /Al₂ O₃molar ratio in the range of about 1 to less than 3, heating said zeoliteand gel at a temperature of from about 150° F. to about 450° F. in witha solution of a salt of a monovalent cation other than alkali metalcation, or a polyvalent cation, or both said cations, and reducing theNH₄ in the treated composite to an amount equivalent to substantiallyless than 0.3 equivalents per mole of Al₂ O₃ in the first mentioned geland reducing the sodium content in the mixture of the treatedcrystalline alumino-silicate zeolite, and gel, to an amount equivalentto less than 5% by weight of the zeolite on a volatile free basis. 3.The process of producing a cracking catalyst which comprises forming asilica-alumina gel having an SiO₂ /Al₂ O₃ molar ratio of more than about1, and less than about 2.5, and associated with sodium ions expressed asNa₂ O of substantially less than about 1% based on the gel on a volatilefree basis, mixing the same with a crystalline alumino silicate Yzeolite and treating said gel, and said Y zeolite, by heating said geland zeolite in a solution containing monovalent cations other thanalkali metal cations, or polyvalent cations, or both said cations, andseparating said gel and Y zeolite.
 4. A process for producing an activecracking catalyst which comprises mixing a crystalline alumino silicateY zeolite having a sodium content expressed as Na₂ O, substantially morethan 5% by weight of the zeolite on a volatile free basis, with anammoniated silica-alumina gel containing NH₄ ions associated with thegel in an amount, substantially in excess of about 0.3 equivalents permole of alumina (Al₂ O₃), and having an SiO₂ /Al₂ O₃ molar ratio in therange of about 1 to less than 3, heating said zeolite and gel at atemperature of from about 150° F. to about 450° F. in a solution of asalt of a monovalent cation other than alkali metal cation, or apolyvalent cation, or both said cations, and reducing the NH₄ in thetreated composite to an amount equivalent to substantially less than 0.3equivalents per mole of Al₂ O₃ in the first mentioned gel and reducingthe sodium content in the mixture of zeolite and gel equivalent to anamount equivalent to Na₂ O, on a volatile free basis, to less than 5% byweight of the zeolite on a volatile free basis.
 5. The process of claim1, 2, 3, or 4, including heating said ammoniated gel and crystallinealumino silicate during said exchange at a temperature of about 150° F.to about 450° F.
 6. The process of claim 1, 2, 3 or 4 in which thesolution is acidified.
 7. The process of claim 1, 2, 3, or 4, in whichthe cation in the solution contains a rare earth cation and saidcrystalline alumino-silicate is a faujasite type zeolite.
 8. The processof claim 1, 2, 3, or 4, including heating said crystalline aluminosilicate encapsulated with the ammoniated gel during said exchange at atemperature of about 150° F. to about 450° F.
 9. The process of claim 1,2, 3, or 4, in which the cation in the solution is a rare earth cation,and said crystalline alumino silicate is encapsulated with theammoniated gel and the encapsulated crystalline alumino silicate and thesaid solution is maintained at a temperature of about 150° F. to about400° F.